Negative electrode black powder and recovery method thereof

Abstract

The invention provides negative electrode black powder and a recovery method thereof. The negative electrode black powder comprises graphite and meets the condition that H (002) / H (111) is larger than or equal to 50, H (002) is the peak intensity of a 002 characteristic diffraction peak in an X-ray diffraction pattern of the negative electrode black powder, and H (111) is the peak intensity of a 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder. According to the method, the ratio of the peak intensity of the 002 characteristic diffraction peak to the peak intensity of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder is controlled to meet a certain range, so that the efficiency of recovering and leaching the lithium by the wet method is improved, the subsequent recovery process is favorably simplified, and the recovery cost is reduced.

Description

Technical Field

[0001] This application relates to the technical field of secondary battery recycling, in particular to a negative electrode black powder and a recycling method thereof. Background Art

[0002] The secondary recycling of lithium resources can solve the problem of the balance between supply and demand of lithium resources, and at the same time bring great economic benefits. Recycling lithium from the negative electrode of retired lithium batteries has the advantages of high recovery rate and high product purity, and has received extensive attention in the industry. Realizing the separation of negative electrode black powder and copper and obtaining negative electrode black powder with high dispersibility and low impurity content is the key link to further improve the lithium recovery rate. Summary of the Invention

[0003] The purpose of this application is to provide a negative electrode black powder and a recycling method thereof to improve the efficiency of leaching lithium by wet recycling, simplify the subsequent recycling process, and reduce the recycling cost.

[0004] To achieve the above purpose, in the first aspect of this application, a negative electrode black powder is provided. The negative electrode black powder contains graphite, and the negative electrode black powder satisfies: H (002) / H (111) ≥50, where H (002) is the peak intensity of the 002 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder, and H (111) is the peak intensity of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder.

[0005] As an embodiment of this application, the negative electrode black powder satisfies: 0.1°≤F (002) ≤0.3°, where F (002) is the full width at half maximum of the 002 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder.

[0006] As an embodiment of this application, the negative electrode black powder satisfies: 0.1°≤F (111) ≤0.3°, where F (111) is the full width at half maximum of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder.

[0007] As an embodiment of this application, there are at least 3 characteristic peaks in the particle size distribution diagram of the negative electrode black powder, and at least 1 characteristic peak exists above 100 μm.

[0008] As an embodiment of this application, the volume percentage H max of the characteristic peak with the largest particle size in the particle size distribution diagram of the negative electrode black powder satisfies: 0.1%≤H max ≤5%.

[0009] As an embodiment of this application, the negative electrode black powder contains lithium, and the content C Li of the lithium satisfies: 1 wt%≤CLi ≤5 wt%.

[0010] As an embodiment of the present application, the negative black powder contains impurity elements, and the impurity elements include at least one of Ni, Co, Mn, Al, Cu, Fe, Mg, B, Ca, Zn, Sb, W, Bi, Cr, Sr, Y, W, Zr, Ti, La, Nb, Mo, V. The total content C of the impurity elements I satisfies: C I ≤5 wt%.

[0011] As an embodiment of the present application, the specific surface area B of the negative black powder satisfies: 1 m 2 / g ≤ B ≤ 5 m 2 / g.

[0012] As an embodiment of the present application, the powder resistivity R of the negative black powder at 20 KN satisfies: 0.01 Ω·cm ≤ R ≤ 0.3 Ω·cm.

[0013] As an embodiment of the present application, the powder compaction density D of the negative black powder at 30 KN satisfies: 1 g / cm 3 ≤ D ≤ 4 g / cm 3 .

[0014] In the second aspect of the present application, a method for recycling negative black powder is provided, including the following steps:

[0015] S1. After discharging the retired secondary battery, disassemble it to obtain the positive electrode sheet, negative electrode sheet and separator;

[0016] S2. Place the negative electrode sheet in a laser cleaning machine, clean it for 20 min to 100 min under the conditions that the laser wavelength is 337 nm to 1064 nm and the cleaning power is 50 W to 800 W, and then screen to obtain the negative black powder;

[0017] The negative black powder contains graphite, and the negative black powder satisfies: H (002) / H (111) ≥50, where H (002) is the peak intensity of the 002 characteristic diffraction peak in the X-ray diffraction pattern of the negative black powder, and H (111) is the peak intensity of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative black powder.

[0018] Compared with the prior art, the beneficial effects of the present application are:

[0019] In the present application, by controlling the peak intensity H (002) of the 002 characteristic diffraction peak and the peak intensity H (111) of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative black powder to satisfy: H (002) / H (111) ≥50, which improves the efficiency of leaching lithium in the wet recovery process, is conducive to simplifying the subsequent recovery process and reducing the recovery cost. Specific Embodiments

[0020] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of them. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0021] In the present application, among the technical features described in an open-ended manner, there are included closed technical solutions composed of the listed features, as well as open technical solutions containing the listed features.

[0022] In the present application, regarding numerical ranges, unless otherwise specified, the above numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when the range refers to integers, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0023] The reagents or instruments used in the present application that are not specified by the manufacturer can all be obtained as conventional products through commercial purchase.

[0024] An embodiment of the present application provides a negative electrode black powder, the negative electrode black powder contains graphite, and the negative electrode black powder satisfies: H (002) / H (111) ≥50, where H (002) is the peak intensity of the 002 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder, and H (111) is the peak intensity of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder.

[0025] The inventors' research found that the ratio of the peak intensity of the 002 characteristic diffraction peak to the peak intensity of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder can reflect the content of copper impurities in the negative electrode black powder. The larger the ratio, the lower the content of copper impurities, which is beneficial to simplifying the subsequent recovery process, reducing the recovery cost, and improving the efficiency of leaching lithium by wet recovery. In this application, the X-ray diffraction pattern of the negative electrode black powder is obtained through the following steps: grinding the sample to be tested into powder for 15 minutes, pressing it into a uniform thin sheet, then loading the sample onto the sample stage of the X-ray diffractometer, and starting the X-ray diffractometer to obtain the corresponding X-ray diffraction pattern. The parameters of the X-ray diffractometer are as follows: target material: Cu target; X-ray measurement wavelength: 1.5406; scanning mode: continuous scanning; starting angle & ending angle: 10° - 90°; scanning speed: 10° / min; step size: 0.01°.

[0026] In some embodiments, the negative electrode black powder satisfies: 50 ≤ H (002) / H (111) ≤ 60.8.

[0027] In some embodiments, the negative electrode black powder satisfies: 0.1° ≤ F (002) ≤ 0.3°, where F (002) is the full width at half maximum of the 002 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder. Exemplarily, the full width at half maximum of the 002 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder can be 0.1°, 0.15°, 0.2°, 0.25°, 0.3° or a value within the range formed by any two of the above. When the full width at half maximum of the 002 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder is within the above range, it is beneficial to improve the efficiency of leaching lithium by wet recovery.

[0028] In some embodiments, the negative electrode black powder satisfies: 0.1° ≤ F (111) ≤ 0.3°, where F (111) is the full width at half maximum of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder. Exemplarily, the full width at half maximum of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder can be 0.1°, 0.15°, 0.2°, 0.25°, 0.3° or a value within the range formed by any two of the above. When the full width at half maximum of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder is within the above range, it is beneficial to improve the efficiency of leaching lithium by wet recovery.

[0029] In some embodiments, there are at least 3 characteristic peaks in the particle size distribution diagram of the negative electrode black powder, and at least 1 characteristic peak exists above 100 μm. When the particle size distribution diagram of the negative electrode black powder meets the above conditions, it is beneficial to improve the leaching efficiency of lithium.

[0030] In some embodiments, the volume percentage H of the characteristic peak with the largest particle size in the particle size distribution diagram of the negative electrode black powder max satisfies: 0.1% ≤ H max ≤ 5%. Exemplarily, the volume percentage H of the characteristic peak with the largest particle size in the particle size distribution diagram of the negative electrode black powder max can be 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or a value within the range formed by any two of the above. When the volume percentage H of the characteristic peak with the largest particle size in the particle size distribution diagram of the negative electrode black powder max is within the above range, the dispersion of the black powder particles is good and the subsequent lithium leaching efficiency is high.

[0031] In some embodiments, the negative electrode black powder contains lithium, and the content C of the lithium Li satisfies: 1 wt% ≤ C Li ≤ 5 wt%. Exemplarily, the content of lithium in the negative electrode black powder can be 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt% or a value within the range formed by any two of the above. When the content of lithium in the negative electrode black powder is within the above range, XX.

[0032] In some embodiments, the negative electrode black powder contains impurity elements, and the impurity elements include at least one of Ni, Co, Mn, Al, Cu, Fe, Mg, B, Ca, Zn, Sb, W, Bi, Cr, Sr, Y, W, Zr, Ti, La, Nb, Mo, V.

[0033] In some embodiments, the total content C of the impurity elements I satisfies: C I ≤ 5 wt%. Exemplarily, the total content C of the impurity elements I can be 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt% or a value within the range formed by any two of the above. When the total content of the impurity elements in the negative electrode black powder is within the above range, it is beneficial to simplify the subsequent recovery process and improve the purity of the recovered lithium product.

[0034] In some embodiments, the specific surface area B of the negative electrode black powder satisfies: 1 m 2 / g ≤ B ≤ 5 m 2 / g. Exemplarily, the specific surface area B of the negative electrode black powder can be 1 m 2 / g, 1.5 m 2 / g, 2 m 2 / g, 2.5 m 2 / g, 3 m2 / g, 3.5 m 2 / g, 4 m 2 / g, 4.5 m 2 / g, 5 m 2 / g or a value within the range formed by any two of the above. When the specific surface area B of the negative electrode black powder is within the above range, it is beneficial to the subsequent leaching of lithium metal elements.

[0035] In some embodiments, the powder resistivity R of the negative electrode black powder 20KN satisfies: 0.01 Ω·cm ≤ R ≤ 0.3 Ω·cm. Exemplarily, the powder resistivity R of the negative electrode black powder 20KN can be 0.01 Ω·cm, 0.05 Ω·cm, 0.1 Ω·cm, 0.15 Ω·cm, 0.2 Ω·cm, 0.25 Ω·cm, 0.3 Ω·cm or a value within the range formed by any two of the above. When the powder resistivity of the negative electrode black powder is within the above range, it is beneficial to the subsequent lithium metal leaching.

[0036] In some embodiments, the powder compaction density D of the negative electrode black powder 30KN satisfies: 1 g / cm 3 ≤ D ≤ 4 g / cm 3 . Exemplarily, the powder compaction density D of the negative electrode black powder 30KN can be 1 g / cm 3 、1.5 g / cm 3 、2 g / cm 3 、2.5 g / cm 3 、3 g / cm 3 、3.5 g / cm 3 、4 g / cm 3 or a value within the range formed by any two of the above. When the powder compaction density of the negative electrode black powder is within the above range, it is beneficial to the subsequent lithium metal leaching.

[0037] In the second aspect of the present application, a method for recycling negative electrode black powder is provided, including the following steps:

[0038] S1. Discharge the retired secondary battery and then disassemble it to obtain the positive electrode plate, negative electrode plate and separator;

[0039] S2. Place the negative electrode plate in a laser cleaning machine, clean it for 20 min to 100 min under the conditions that the laser wavelength is 337 nm to 1064 nm and the cleaning power is 50 W to 800 W, and then screen to obtain the negative electrode black powder;

[0040] The negative electrode black powder contains graphite, and the negative electrode black powder satisfies: H (002) / H (111) ≥ 50, where H (002) is the peak intensity of the 002 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder, and H (111)is the peak intensity of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder.

[0041] In this application, a method of laser cleaning is used to recover the negative electrode black powder. Laser cleaning does not require a cleaning medium, greatly reducing the damage to the copper foil. The copper impurity content in the negative electrode black powder is low, which is beneficial to simplifying the subsequent recovery process and reducing the recovery cost. In addition, laser cleaning removes the negative electrode black powder from the surface of the current collector copper foil through the effects of vaporization, shock waves, and thermal elasticity. The recovery rate of the negative electrode black powder is high and the dispersion is good, significantly improving the efficiency of subsequent wet leaching of lithium.

[0042] The following are specific embodiments of this application, and the technical solutions of this application are further described in combination with the embodiments, but this application is not limited to these embodiments. The reagents, methods, and equipment used in this application are all conventional reagents, methods, and equipment in the technical field unless otherwise specified.

[0043] Example 1

[0044] Example 1 provides a method for recovering negative electrode black powder, including the following steps:

[0045] S1. After completely discharging the retired lithium battery using a discharging device, perform automated disassembly to obtain the positive electrode plate, negative electrode plate, and separator respectively;

[0046] S2. Put the negative electrode plate obtained in step S1 into a laser cleaning machine, and under the conditions of a laser wavelength of 1064 nm and a cleaning power of 50 W, clean each side for 20 min to obtain a mixture of black powder and copper foil;

[0047] S3. Add the mixture obtained in step S2 to a vibrating screen with a screen hole size of 0.2 mm and a screening time of 0.5 h to obtain the negative electrode black powder.

[0048] Example 2

[0049] The method for recovering negative electrode black powder in Example 2 is basically the same as that in Example 1, except that the cleaning power is 100 W.

[0050] Example 3

[0051] The method for recovering negative electrode black powder in Example 3 is basically the same as that in Example 1, except that the cleaning power is 150 W.

[0052] Example 4

[0053] The method for recovering negative electrode black powder in Example 4 is basically the same as that in Example 1, except that the cleaning power is 200 W.

[0054] Example 5

[0055] The method for recovering the black powder of the negative electrode in Example 5 is basically the same as that in Example 1, except that the cleaning power is 300W.

[0056] Example 6

[0057] The method for recovering the black powder of the negative electrode in Example 6 is basically the same as that in Example 1, except that the cleaning power is 400W.

[0058] Example 7

[0059] The method for recovering the black powder of the negative electrode in Example 7 is basically the same as that in Example 1, except that the cleaning power is 500W.

[0060] Example 8

[0061] The method for recovering the black powder of the negative electrode in Example 8 is basically the same as that in Example 1, except that the cleaning power is 800W.

[0062] Example 9

[0063] The method for recovering the black powder of the negative electrode in Example 9 is basically the same as that in Example 1, except that the laser cleaning wavelength is 694nm.

[0064] Example 10

[0065] The method for recovering the black powder of the negative electrode in Example 10 is basically the same as that in Example 1, except that the laser cleaning wavelength is 659nm.

[0066] Example 11

[0067] The method for recovering the black powder of the negative electrode in Example 11 is basically the same as that in Example 1, except that the laser cleaning wavelength is 570nm.

[0068] Example 12

[0069] The method for recovering the black powder of the negative electrode in Example 12 is basically the same as that in Example 1, except that the laser cleaning wavelength is 550nm.

[0070] Example 13

[0071] The method for recovering the black powder of the negative electrode in Example 13 is basically the same as that in Example 1, except that the laser cleaning wavelength is 543nm.

[0072] Example 14

[0073] The method for recovering the black powder of the negative electrode in Example 14 is basically the same as that in Example 1, except that the laser cleaning wavelength is 514nm.

[0074] Example 15

[0075] The method for recovering the negative electrode black powder in Example 15 is basically the same as that in Example 1, except that the laser cleaning wavelength is 488 nm.

[0076] Example 16

[0077] The method for recovering the negative electrode black powder in Example 16 is basically the same as that in Example 1, except that the laser cleaning wavelength is 337 nm.

[0078] Example 17

[0079] The method for recovering the negative electrode black powder in Example 17 is basically the same as that in Example 1, except that the laser cleaning time is 30 min.

[0080] Example 18

[0081] The method for recovering the negative electrode black powder in Example 18 is basically the same as that in Example 1, except that the laser cleaning time is 40 min.

[0082] Example 19

[0083] The method for recovering the negative electrode black powder in Example 19 is basically the same as that in Example 1, except that the laser cleaning time is 50 min.

[0084] Example 20

[0085] The method for recovering the negative electrode black powder in Example 20 is basically the same as that in Example 1, except that the laser cleaning time is 60 min.

[0086] Example 21

[0087] The method for recovering the negative electrode black powder in Example 21 is basically the same as that in Example 1, except that the laser cleaning time is 70 min.

[0088] Example 22

[0089] The method for recovering the negative electrode black powder in Example 22 is basically the same as that in Example 1, except that the laser cleaning time is 80 min.

[0090] Example 23

[0091] The method for recovering the negative electrode black powder in Example 23 is basically the same as that in Example 1, except that the laser cleaning time is 90 min.

[0092] Example 24

[0093] The method for recovering the negative electrode black powder in Example 24 is basically the same as that in Example 1, except that the laser cleaning time is 100 min.

[0094] Comparative Example 1

[0095] The recovery method of the negative electrode black powder of Comparative Example 1 is basically the same as that of Example 1, except that the laser power is 2000 W, the laser wavelength is 248 nm, and the laser cleaning time is 200 min.

[0096] Comparative Example 2

[0097] The recovery method of the negative electrode black powder of Comparative Example 2 is basically the same as that of Example 1, except that the laser power is 3000 W, the laser wavelength is 2100 nm, and the laser cleaning time is 150 min.

[0098] The physical property parameters of the negative electrode black powder and the parameters of the recovery method of the negative electrode black powder in Examples 1 to 24 and Comparative Examples 1 to 2 are shown in Table 1.

[0099] Test Example

[0100] Using 2M sulfuric acid as the immersion agent, the recovered negative electrode black powder is chemically leached under the conditions of 45 °C, a solid-liquid ratio of 100 g / L, a stirring speed of 1000 rpm, and a reaction time of 20 min. The lithium metal leaching efficiency is shown in Table 1.

[0101] Table 1

[0102]

[0103]

[0104] Table 1 (continued)

[0105]

[0106]

[0107] From the above examples and comparative examples, by controlling the peak intensity H of the 002 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder (002) and the peak intensity H of the 111 characteristic diffraction peak (111) satisfy: H (002) / H (111) ≥50, the leaching efficiency of lithium in the wet recovery is improved, which is beneficial to simplifying the subsequent recovery process and reducing the recovery cost.

[0108] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A negative electrode black powder, characterized in that: The negative electrode black powder contains graphite, and the negative electrode black powder satisfies: H (002) / H (111) ≥50, where H (002) is the peak intensity of the 002 characteristic diffraction peak in the X-ray diffraction spectrum of the negative electrode black powder, H (111) It is the peak intensity of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder.

2. The negative electrode black powder according to claim 1, characterized in that: The negative electrode black powder satisfies at least one of the following conditions: (1)0.1°≤F (002) ≤0.3°； (2)0.1°≤F (111) ≤0.3°； Among them, F (002) is the half-peak width of the 002 characteristic diffraction peak in the X-ray diffraction spectrum of the negative electrode black powder, F (111) It is the half-peak width of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder.

3. The negative electrode black powder according to claim 1, characterized in that: There are at least three characteristic peaks in the particle size distribution diagram of the negative electrode black powder, and at least one characteristic peak exists above 100 μm.

4. The negative electrode black powder according to claim 3, characterized in that: The volume percentage H of the characteristic peak with the largest particle size in the particle size distribution diagram of the negative electrode black powder max Satisfy: 0.1% ≤ H max ≤5%.

5. The negative electrode black powder according to claim 1, characterized in that: The negative electrode black powder contains lithium, and the content of lithium is C Li Satisfy: 1wt%≤C Li ≤5wt%.

6. The negative electrode black powder according to claim 1, characterized in that: The negative electrode black powder contains impurity elements, and the impurity elements include at least one of Ni, Co, Mn, Al, Cu, Fe, Mg, B, Ca, Zn, Sb, W, Bi, Cr, Sr, Y, W, Zr, Ti, La, Nb, Mo, and V. The total content of the impurity elements is C I Satisfaction: C I ≤5wt%.

7. The negative electrode black powder according to claim 1, characterized in that: The specific surface area B of the negative electrode black powder satisfies: 1m 2 / g≤B≤5m 2 / g.

8. The negative electrode black powder according to claim 1, characterized in that: The powder resistivity R of the negative electrode black powder 20KN satisfies: 0.01Ω*cm≤R≤0.3Ω*cm.

9. The negative electrode black powder according to claim 1, characterized in that: The compacted density D of the negative electrode black powder 30KN satisfies: 1g / cm 3 ≤D≤4g / cm 3 .

10. A method for recovering negative electrode black powder, characterized in that: The steps include: S1. Dismantle the retired secondary battery after discharging to obtain the positive electrode sheet, the negative electrode sheet and the separator; S2. Place the negative electrode sheet in a laser cleaning machine, clean it for 20 min to 100 min under the conditions of a laser wavelength of 337 nm to 1064 nm and a cleaning power of 50 W to 800 W, and then sieve to obtain negative electrode black powder; The negative electrode black powder contains graphite, and the negative electrode black powder satisfies: H (002) / H (111) ≥50, where H (002) is the peak intensity of the 002 characteristic diffraction peak in the X-ray diffraction spectrum of the negative electrode black powder, H (111) It is the peak intensity of the 111 characteristic diffraction peak in the X-ray diffraction pattern of the negative electrode black powder.

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